I have revised my list. $50 Million is a whole lot of money and my initial choice was a little "light". So here are my updated choices:
My cars would be 4 MG-Xpower SV, all painted black with flourescent green flames
With a mix of CART, Sportscar, F3000 drivers and me of course
Then I would spend the rest of my money making sure those slow Porsches stay out of our way